As well known in the art, optical isomers generally have different activities to living bodies, even though they are chemically the same compounds. Accordingly, in the fields of pharmaceuticals, pharmaceutical manufacture and biochemistry-related industries, it is an extremely important task to prepare optically pure compounds in order to improve the efficacy of pharmaceuticals per unit dose and to avoid the side effects and damages caused by pharmaceuticals. The separation of an optical isomer mixture, that is, optical resolution, has been performed according to the diastereomer method, the crystallization method, the enzyme method and the separating membrane method. In these methods, however, the types of compounds for which optical resolution is feasible are often limited, so that they are not suitable for general purposes. Although chromatography is available for such separation, currently known chromatographic methods are of batch type, so that noncontinuous and nonsteady operations are inevitable and hence they are not suitable for the separation in a large quantity. In addition, a large quantity of an eluent is needed to and the concentration of the desired compound in an eluate is extremely low, so that there has been a drawback that much energy and complicated process are required for recovery. Therefore, the development of a method capable of efficient separation in a large quantity has been desired in the art.